I use MacOS screen sharing to power pair programming sessions that I have in my development team. There are two modes for the navigator to use when observing the driver's screen (assuming that the screen being shared is of the driver): Observe Mode to disallow taking control of the screen, or a self-explanatory Control Mode.
I like being in Observe Mode as the navigator so that I don't mistakingly take control of the driver's screen and start polluting the screen with accidental key strokes. But if I ever need to switch control, I would have to then make a mouse click on the correct icon. This gets annoying if I am observing in Full Screen mode (which is almost always). I would have to exit full screen mode first in order to switch to taking control.
**SOLUTION:** I can instead use the CMD-ALT-X key combination to quickly switch control mode :D